Magnetic field sensors have a broad field of use. Magnetic field sensors are often used in combination with magnetic field generators, such as simple magnets, to determine positions of mechanical components. In an automobile, magnetic field sensors are often used to determine positions of rotational components, such as shafts, or translational components, such as valves. Hall sensors are distinguished, in comparison with giant magnetoresistance (GMR) sensors, by the fact that Hall sensors measure the magnetic field component that is perpendicular to the Hall sensor.
A use in safety-relevant applications requires a very high operating safety of the components used, that is to say also a very high operating safety in the case of magnetic field sensors. As an example of the requirements made of safety-relevant systems, or components, IEC 61508 shall be cited, which finds application in the automotive industry.
Takehashi et al. disclose in U.S. Pat. No. 5,783,463 an arrangement and a method for realizing a multi-chip housing in order to obtain a lighter and smaller housing. This housing enables smaller and lighter electronic machines.
Strack et al. disclose in DE 198 15 906 a housing for a power semiconductor, and a larger surface for semiconductor chips is available in the component.
Außerlechner discloses in DE 103 15 532 a current sensor device of integrated embodiment. In this case, a structure through which current flows generates a magnetic field, such that a current is measured indirectly by way of the magnetic field generated by the current. The GMR sensors are connected to one another via an electrical connection. Since the magnetic field lines generated by the current enclose the current conductor, a magnetic field sensor is required which reacts to horizontal magnetic field lines with respect to the magnetic field sensor, such that the use of GMR sensors is required here.
The data sheet of the MLX90277 from Melexis describes a “Dual Programmable Linear Hall Effect Sensor” in which two discrete CMOS ICs are arranged in a single housing such that they are electrically insulated and independently programmable.
The use of magnetic field sensors in a safety-relevant area, such as an automobile, for example, necessitates dispensing with components which can adversely influence the lifetime of a magnetic field sensor, such as, for example, moisture-sensitive substances in a semiconductor housing.
The use of magnetic field sensors in a safety-relevant area, such as an automobile, for example, additionally requires redundant or partly redundant systems.
Despite the stringent requirements made of safety, reliability and redundancy, magnetic field sensors, particularly in an automobile, have to be inexpensive.